Various compositions are utilized in situ to seal defects and/or leaks, as well as adsorb body fluids, including blood. For example, materials utilized in situ include hemostats, adhesives, sealants, hydrogels, combinations thereof, and the like.
Hydrogels are materials that absorb solvents (such as water), undergo rapid swelling without discernible dissolution, and maintain three-dimensional networks capable of reversible deformation.
One issue that may arise with the delivery of materials capable of forming adhesives, sealants, hemostats, hydrogels, and the like, in situ, is that the precursors utilized to form the material may begin to gel during dispensing from any delivery device, which may clog the dispensing apparatus utilized to deliver the hydrogel. For example, some adhesives, hydrogels, and sealants that are produced upon the admixture of more than one precursor may, depending upon the pH of the local environment, gel within about 3.5 seconds after the precursors have contacted each other. Changes in the pH of the local environment may alter the reaction kinetics of such adhesives, hydrogels and sealants to speed up or slow down gelling of the precursors.
Thus, conventional devices utilized to deliver such materials often come with multiple tips, which may have to be changed during a surgical procedure, due to premature gelling and clogging. Similarly, for devices which dispense such materials without the use of a tip, premature gelling and clogging may result in the failure of the applicator system or suboptimal performance during a surgical procedure.
It would be desirable to provide methods and apparatus for introducing materials capable of forming in situ that avoid premature gelling and/or clogging of the dispensing or delivery device.